President Bush's Republican Party will maintain control of the U.S. Congress following Tuesday's elections. In a major upset, Senate Democratic leader Tom Daschle of South Dakota lost his seat to a former Republican Congressman. Correspondent Deborah Tate reports from Capitol Hill.

Mr. Daschle becomes the first Senate party leader in half a century to lose a re-election bid. In a bitterly-fought contest, the South Dakota Democrat lost to former Republican Congressman John Thune.

In the early hours of Wednesday morning, Mr. Thune thanked his supporters at a victory party.

"Without further ado, it is a little early in the morning, but I think everyone has a little celebrating to do," he said.

Republicans expanded their current 51 seat majority in the Senate. They won seats being vacated by retiring Democratic senators in Georgia, North Carolina and South Carolina. Louisiana Congressman David Vitter is expected to became the first Republican since the post-Civil War Reconstruction era to win the open Senate seat in that state.

Republicans maintained seats in close races in Oklahoma and Kentucky, where Democrats hoped to make gains.

Democrats did pick up a seat in Illinois, where State Senator Barack Obama, son of a Kenyan father and American mother, easily won the seat being vacated by Republican Senator Peter Fitzgerald. Mr. Obama, who delivered the keynote address at the Democratic National Convention in July, will be the only African-American in the Senate, when a new Congress convenes in January.

He was exuberant when he addressed supporters Tuesday night.

"I am fired up. Look at this crowd. Thank you Illinois!" he exclaimed.

In Colorado, Democratic State Attorney General Ken Salazar is expected to win the seat held by retiring Republican Ben Nighthorse Campbell.

In all, 34 Senate seats were up for election.

In the House, where all 435 seats were on the ballot, Republicans also gained several seats. Majority Leader Tom Delay is pleased his party will maintain control of the chamber.

"The American people have spoken tonight, and all indications are that they have hired a Republican House of Representatives for the sixth straight election," he said.

But Republicans suffered one key defeat: Illinois Congressman Phil Crane, the longest-serving Republican in the House, lost his seat to Democratic challenger Melissa Bean.

On the Democratic side, veteran Texas Congressmen Martin Frost and Charles Stenholm lost their seats, after state Republicans redrew congressional district lines to their party's advantage.